Well I'll play the advocate. R3 blocks are very very rare and expensive. If I was going with one I would get a siamese bore that way you could freshen it up many many many times. Also just because you have an R3 doesn't mean they will handle anything you throw at them. They are castings just the same as production blocks and even Ryan himself has seen bad core shifts, missing bolt holes, very small oil passages ect... So just keep that in mind when buying one. If it were my build I just sit tight for a bit and wait on the XP blocks.